Rename persistJob() to persistState() and remove impl details from doc

Author: dimitris-athanasiou

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/job/process/autodetect/AutodetectCommunicator.java

@@ -264,7 +264,7 @@ public void forecastJob(ForecastParams params, BiConsumer<Void, Exception> handl
 
     public void persistJob(BiConsumer<Void, Exception> handler) {
         submitOperation(() -> {
-            autodetectProcess.persistJob();
+            autodetectProcess.persistState();
             return null;
         }, handler);
     }

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/job/process/autodetect/BlackHoleAutodetectProcess.java

@@ -96,7 +96,7 @@ public String flushJob(FlushJobParams params) throws IOException {
     }
 
     @Override
-    public void persistJob() {
+    public void persistState() {
     }
 
     @Override

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/job/process/autodetect/NativeAutodetectProcess.java

@@ -105,7 +105,7 @@ public void forecastJob(ForecastParams params) throws IOException {
     }
 
     @Override
-    public void persistJob() throws IOException {
+    public void persistState() throws IOException {
         newMessageWriter().writeStartBackgroundPersistMessage();
     }
 

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/job/process/normalizer/MultiplyingNormalizerProcess.java

@@ -81,7 +81,7 @@ public void writeRecord(String[] record) throws IOException {
     }
 
     @Override
-    public void persistJob() {
+    public void persistState() {
         // Nothing to do
     }
 

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/job/process/normalizer/NativeNormalizerProcess.java

@@ -34,7 +34,7 @@ public boolean isReady() {
     }
 
     @Override
-    public void persistJob() {
+    public void persistState() {
         // nothing to persist
     }
 

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/process/NativeProcess.java

@@ -34,7 +34,7 @@ public interface NativeProcess extends Closeable {
      * Ask the process to persist its state in the background
      * @throws IOException If writing the request fails
      */
-    void persistJob() throws IOException;
+    void persistState() throws IOException;
 
     /**
      * Flush the output data stream
@@ -64,14 +64,14 @@ public interface NativeProcess extends Closeable {
     boolean isProcessAlive();
 
     /**
-     * Check whether the process terminated given maximum 45ms for termination
+     * Check whether the process terminated given a grace period.
      *
      * Processing errors are highly likely caused by the process being unexpectedly
      * terminated.
      *
      * Workaround: As we can not easily check if the process is alive, we rely on
      * the logPipe being ended. As the loghandler runs in another thread which
-     * might fall behind this one, we give it a grace period of 45ms.
+     * might fall behind this one, we give it a grace period.
      *
      * @return false if process has ended for sure, true if it probably still runs
      */

x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/job/process/autodetect/NativeAutodetectProcessTests.java

@@ -128,7 +128,7 @@ public void testWriteUpdateConfigMessage() throws IOException {
     }
 
     public void testPersistJob() throws IOException {
-        testWriteMessage(p -> p.persistJob(), ControlMsgToProcessWriter.BACKGROUND_PERSIST_MESSAGE_CODE);
+        testWriteMessage(p -> p.persistState(), ControlMsgToProcessWriter.BACKGROUND_PERSIST_MESSAGE_CODE);
     }
 
     public void testWriteMessage(CheckedConsumer<NativeAutodetectProcess> writeFunction, String expectedMessageCode) throws IOException {